diff --git a/target/hexagon/gen_dectree_import.c b/target/hexagon/gen_dectree_import.c
new file mode 100644
index 0000000000..5b7ecfc6b3
--- /dev/null
+++ b/target/hexagon/gen_dectree_import.c
@@ -0,0 +1,188 @@
+/*
+ *  Copyright(c) 2019-2021 Qualcomm Innovation Center, Inc. All Rights Reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * This program generates the encodings file that is processed by
+ * the dectree.py script to produce the decoding tree.  We use the C
+ * preprocessor to manipulate the files imported from the Hexagon
+ * architecture library.
+ */
+#include <stdio.h>
+#include <string.h>
+#include "opcodes.h"
+
+#define STRINGIZE(X)    #X
+
+const char * const opcode_names[] = {
+#define OPCODE(IID) STRINGIZE(IID)
+#include "opcodes_def_generated.h.inc"
+    NULL
+#undef OPCODE
+};
+
+/*
+ * Process the instruction definitions
+ *     Scalar core instructions have the following form
+ *         Q6INSN(A2_add,"Rd32=add(Rs32,Rt32)",ATTRIBS(),
+ *         "Add 32-bit registers",
+ *         { RdV=RsV+RtV;})
+ */
+const char * const opcode_syntax[XX_LAST_OPCODE] = {
+#define Q6INSN(TAG, BEH, ATTRIBS, DESCR, SEM) \
+   [TAG] = BEH,
+#define EXTINSN(TAG, BEH, ATTRIBS, DESCR, SEM) \
+   [TAG] = BEH,
+#include "imported/allidefs.def"
+#undef Q6INSN
+#undef EXTINSN
+};
+
+const char * const opcode_rregs[] = {
+#define REGINFO(TAG, REGINFO, RREGS, WREGS) RREGS,
+#define IMMINFO(TAG, SIGN, SIZE, SHAMT, SIGN2, SIZE2, SHAMT2)  /* nothing */
+#include "op_regs_generated.h.inc"
+    NULL
+#undef REGINFO
+#undef IMMINFO
+};
+
+const char * const opcode_wregs[] = {
+#define REGINFO(TAG, REGINFO, RREGS, WREGS) WREGS,
+#define IMMINFO(TAG, SIGN, SIZE, SHAMT, SIGN2, SIZE2, SHAMT2)  /* nothing */
+#include "op_regs_generated.h.inc"
+    NULL
+#undef REGINFO
+#undef IMMINFO
+};
+
+const OpcodeEncoding opcode_encodings[] = {
+#define DEF_ENC32(TAG, ENCSTR) \
+    [TAG] = { .encoding = ENCSTR },
+#define DEF_ENC_SUBINSN(TAG, CLASS, ENCSTR) \
+    [TAG] = { .encoding = ENCSTR, .enc_class = CLASS },
+#define DEF_EXT_ENC(TAG, CLASS, ENCSTR) \
+    [TAG] = { .encoding = ENCSTR, .enc_class = CLASS },
+#include "imported/encode.def"
+#undef DEF_ENC32
+#undef DEF_ENC_SUBINSN
+#undef DEF_EXT_ENC
+};
+
+static const char * const opcode_enc_class_names[XX_LAST_ENC_CLASS] = {
+    "NORMAL",
+    "16BIT",
+    "SUBINSN_A",
+    "SUBINSN_L1",
+    "SUBINSN_L2",
+    "SUBINSN_S1",
+    "SUBINSN_S2",
+    "EXT_noext",
+    "EXT_mmvec",
+};
+
+static const char *get_opcode_enc(int opcode)
+{
+    const char *tmp = opcode_encodings[opcode].encoding;
+    if (tmp == NULL) {
+        tmp = "MISSING ENCODING";
+    }
+    return tmp;
+}
+
+static const char *get_opcode_enc_class(int opcode)
+{
+    return opcode_enc_class_names[opcode_encodings[opcode].enc_class];
+}
+
+static void gen_iset_table(FILE *out)
+{
+    int i;
+
+    fprintf(out, "iset = {\n");
+    for (i = 0; i < XX_LAST_OPCODE; i++) {
+        fprintf(out, "\t\'%s\' : {\n", opcode_names[i]);
+        fprintf(out, "\t\t\'tag\' : \'%s\',\n", opcode_names[i]);
+        fprintf(out, "\t\t\'syntax\' : \'%s\',\n", opcode_syntax[i]);
+        fprintf(out, "\t\t\'rregs\' : \'%s\',\n", opcode_rregs[i]);
+        fprintf(out, "\t\t\'wregs\' : \'%s\',\n", opcode_wregs[i]);
+        fprintf(out, "\t\t\'enc\' : \'%s\',\n", get_opcode_enc(i));
+        fprintf(out, "\t\t\'enc_class\' : \'%s\',\n", get_opcode_enc_class(i));
+        fprintf(out, "\t},\n");
+    }
+    fprintf(out, "};\n\n");
+}
+
+static void gen_tags_list(FILE *out)
+{
+    int i;
+
+    fprintf(out, "tags = [\n");
+    for (i = 0; i < XX_LAST_OPCODE; i++) {
+        fprintf(out, "\t\'%s\',\n", opcode_names[i]);
+    }
+    fprintf(out, "];\n\n");
+}
+
+static void gen_enc_ext_spaces_table(FILE *out)
+{
+    fprintf(out, "enc_ext_spaces = {\n");
+#define DEF_EXT_SPACE(SPACEID, ENCSTR) \
+    fprintf(out, "\t\'%s\' : \'%s\',\n", #SPACEID, ENCSTR);
+#include "imported/encode.def"
+#undef DEF_EXT_SPACE
+    fprintf(out, "};\n\n");
+}
+
+static void gen_subinsn_groupings_table(FILE *out)
+{
+    fprintf(out, "subinsn_groupings = {\n");
+#define DEF_PACKED32(TAG, TYPEA, TYPEB, ENCSTR) \
+    do { \
+        fprintf(out, "\t\'%s\' : {\n", #TAG); \
+        fprintf(out, "\t\t\'name\' : \'%s\',\n", #TAG); \
+        fprintf(out, "\t\t\'class_a\' : \'%s\',\n", #TYPEA); \
+        fprintf(out, "\t\t\'class_b\' : \'%s\',\n", #TYPEB); \
+        fprintf(out, "\t\t\'enc\' : \'%s\',\n", ENCSTR); \
+        fprintf(out, "\t},\n"); \
+    } while (0);
+#include "imported/encode.def"
+#undef DEF_PACKED32
+    fprintf(out, "};\n\n");
+}
+
+int main(int argc, char *argv[])
+{
+    FILE *outfile;
+
+    if (argc != 2) {
+        fprintf(stderr, "Usage: gen_dectree_import ouptputfile\n");
+        return 1;
+    }
+    outfile = fopen(argv[1], "w");
+    if (outfile == NULL) {
+        fprintf(stderr, "Cannot open %s for writing\n", argv[1]);
+        return 1;
+    }
+
+    gen_iset_table(outfile);
+    gen_tags_list(outfile);
+    gen_enc_ext_spaces_table(outfile);
+    gen_subinsn_groupings_table(outfile);
+
+    fclose(outfile);
+    return 0;
+}
